In semiconductor fabrication systems, the presence of contaminants is a significant contributor to yield reduction. As a result serious effort is dedicated to identifying and removing the sources of contamination. One new family of tools used for identifying contaminants is “Surface Extraction System. In particular, Particle Measuring Systems (of Bolder, Colo.) has developed a particle extraction system, named SURFEX, for monitoring and qualifying the cleanliness of components. Simply, sample parts are loaded into the surface extraction system and the system washes the samples in an ultrasonic bath. The wash solution is then analyzed to detect the presence, type, and amount of contaminants in the wash solution. Such tools are effective in analyzing samples difficult to analyze by other methods.
However, one of the difficulties in such surface extraction systems is that is very difficult to quantify the reliability of results obtained by such systems. Moreover, it is difficult to determine whether results obtained by the system are repeatable. Existing “calibration” methods focus on detecting the presence of a contaminant of known size in the wash solution, but have no quantitative way of correlating this to the level of contamination one the samples. Additionally, such methods are not able to repeatably demonstrate that samples with a cetain level of contamination produce repeatable results using such surface extraction systems.
One reason why calibration has not yet been possible, is due the lack of a cost-effective standard against which to measure the results produced by the system. In short, as far as the inventor is aware, there is no cost-effective uniformly contaminated standard available for use with the surface extraction system. Nor are there methodologies for creating such uniformly contaminated standards.
Thus, what is needed is a method and apparatus of uniformly contaminating a standard for use in such surface extraction systems. Additionally, the inventor contemplates that such method and apparatus can be used to fabricate (among other things) uniformly contaminated semiconductor wafers that can be used for a number of applications in the semiconductor fabrication industry.